The present invention relates to a membrane separation apparatus and, more specifically, relates to an improved filter module of the hollow fiber type, and a method of manufacturing such a module.
The membrane separation process is an operation that separates one or more components from a liquid comprising those components (and possibly other components) by the use of a membrane having a selective permeability to the liquid. Thus, depending on the permeability of the membrane, certain components can be filtered from the liquid while other components remain.
Despite many developments and improvements in hollow fiber filtration modules, the challenge to optimize the operability, efficiency, and durability of the modules continues. The hollow fibers of a conventional membrane separation apparatus are arranged tightly and uniformly around a hollow perforated pipe so that liquid is filtered through the hollow fibers and then collected and removed from the filter module by the hollow perforated pipe. Unfortunately, however, filtered liquid often does not flow efficiently from the individual fiber elements to the hollow tube, due to the dense packing of the fibers within a typical filter module. The impeded flow of the filtered liquid results in the filtered liquid flowing at a reduced rate of speed and, accordingly, increases the pressure differential required to operate the filter module at a given volume.